The enzyme system responsible for the conversion of dihydrodipiciolinic acid, and intermediate in lysine boisynthesis, to dipicolinic acid will be purified and characterized. A detailed comparison of the properties of normal B.megaterium spores and spores containing 4-H-pyran-2,6-dicarboxylate in place of dipicolinic acid will be carried out in order to provide information on the role of dipicolinic acid in spore physiology. A new procedure for determining the extent and rate of cross-linking of diaminopimelic acid in bacterial cell walls has been devised. The method will be employed to provide information on the control of the cross-linking reaction and the basis of its sensitivity to penicillin.